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Commentators have recommended that forensic scientists' reports contain various disclosures to facilitate comprehension. However, little research has explored whether following best practice recommendations for disclosure impacts on receivers' impressions of the evidence. We examined whether forensic science reports that are more compliant with these best practice recommendations reduced overvaluing of the evidence and sensitized legal and community decision-makers to evidence quality. Across three experiments, 240 legal practitioners/trainees and 566 community decision-makers were presented with a fingerprint or footwear report that was either compliant or non-compliant with best practice recommendations. Participants were then asked to make evaluations and decisions based on the report. We found mixed effects of report compliance. Report compliance affected community participant's evaluations of the persuasiveness of the evidence but had limited impact on the judgments of legal practitioners/trainees. When presented with compliant reports, we found that community participants regarded unknown reliability evidence as less reliable and less persuasive than high reliability evidence, suggesting disclosures helped reduce overvaluing of the evidence and create sensitivity to differences in evidence quality. These results suggest compliance with reporting recommendations does affect community impressions, while only minimally influencing legal impressions of forensic science evidence. The costs and/or benefits of this outcome require further examination., Competing Interests: Declaration of Competing Interest Summersby, S and Ballantyne, K.N. are employees of Victoria Police Forensic Services Department. Edmond G, Kemp, R .I, and Martire, K.A declare no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

There is limited information available about the impact of chemical trace evidence and it has tended to be anecdotal and mostly pertaining to court outcomes. Very little is known about the use of chemical trace evidence by police investigators or the impact that this evidence form has on criminal investigations. This survey, which was conducted in Victoria, Australia, was aimed at addressing these inadequacies by capturing information from police investigators about: (i) the purpose of using chemical trace and other forensic services; (ii) the expectation of what value forensic services would provide; (iii) the actual impact of forensic evidence in specified cases; and (iv) the general perceptions of forensic science. Police officers who were the lead investigators in a sample of criminal investigations were selected as the subjects for this survey. Each of the sample cases included chemical trace evidence and many of the cases also included other forms of forensic evidence. The police investigators indicated that they use chemical trace evidence with the expectation that it will assist decision-making in their investigations and contribute to building a case for court. Survey responses indicated that chemical trace evidence can impact on multiple stages of a case and that this form of evidence can play a part in guiding police investigators in making decisions about how their cases progress through the criminal justice system. It was found that an important aspect of the impact of chemical trace evidence can involve connections with other forensic and non-forensic evidence in the cases. The provision of preliminary results, prior to the formal written reports that are issued for use in court, enables chemical trace evidence to contribute timely support to investigations. The findings of this survey study contradict prevailing perceptions that the contribution of chemical trace evidence is limited to the presentation of evidence in court., Competing Interests: Declaration of Competing Interest Peter Woodman and Kaye Ballantyne were employees of VPFSD at the time of the study. However, the study was conducted as an independent piece of research under the supervision of the other authors who are external to the organisation., (Crown Copyright © 2020. Published by Elsevier B.V. All rights reserved.)

The focus of this research was to examine the contribution chemical trace evidence makes to criminal justice outcomes. The aim of this work was to place the discipline of chemical trace evidence under the spotlight as there is a dearth of robust research on the impact of this discipline. In this study, data relating to the forensic examinations in a sample of 238 cases which included chemical trace evidence, was collated with data from police investigations and court processes. The findings show that chemical trace evidence is frequently used in combination with other forensic disciplines to support the progress of high-level criminal cases through the justice system. Due to characteristics of how the criminal cases in the dataset were investigated and prosecuted, in combination with the methodology applied in this study, the impact of forensic evidence on the decision to charge suspects could not be analysed quantitatively. However, the impact of forensic evidence on court outcomes in the sample of cases was analysed using methodology that considered the results of the examinations, and the ability of the evidence to provide support for the inclusion or exclusion of persons of interest. The possibility of chemical trace evidence having impact when applied in combination with other forensic disciplines was also examined. It was found that biological examination results was a significant standalone predictor of court outcomes. In contrast, chemical trace examinations did not predict court outcomes when considered as a standalone predictor but examination results of chemical trace evidence in combination with ballistics/tool marks was significantly associated with court outcomes. The findings of this research indicate that, to assess the full impact of any discipline of forensic evidence on the criminal justice system, the analysis must take into account the potential for important synergies that may exist with other forensic and non-forensic evidence., Competing Interests: Declaration of Competing Interest Peter Woodman and Kaye Ballantyne were employees of VPFSD at the time of the study. However, the study was conducted as an independent piece of research under the supervision of the other authors who are external to the organisation., (Copyright © 2019. Published by Elsevier B.V.)

We do not know how often false positive reports are made in a range of forensic science disciplines. In the absence of this information it is important to understand the naive beliefs held by potential jurors about forensic science evidence reliability. It is these beliefs that will shape evaluations at trial. This descriptive study adds to our knowledge about naive beliefs by: (1) measuring jury-eligible (lay) perceptions of reliability for the largest range of forensic science disciplines to date, over three waves of data collection between 2011 and 2016 (n=674); (2) calibrating reliability ratings with false positive report estimates; and (3) comparing lay reliability estimates with those of an opportunity sample of forensic practitioners (n=53). Overall the data suggest that both jury-eligible participants and practitioners consider forensic evidence highly reliable. When compared to best or plausible estimates of reliability and error in the forensic sciences these views appear to overestimate reliability and underestimate the frequency of false positive errors. This result highlights the importance of collecting and disseminating empirically derived estimates of false positive error rates to ensure that practitioners and potential jurors have a realistic impression of the value of forensic science evidence., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Bloodstain evidence can be very powerful evidence in assault related crimes. Determination of the distance that blood droplets may travel as a result of an impact into liquid blood may be of significance to corroborate or disprove a version of events, provide likely scenarios, or help determine the culpability of a person in determining their proximity to the blood shedding event. It was the aim of this research to determine the potential maximum distance blood droplets travel horizontally following a vertical impact into liquid blood. A custom apparatus was designed and constructed to replicate a vertical impact of a timber weapon, rotating on a fixed axis at one end, striking a pool of liquid blood. The device was positioned at three different levels of elevation to replicate an impact to the head of a person near ground level, a seated or kneeling height and standing height. Overall, the results indicated that the application of kinetic energy of between 1 and 5J at a height of 1780mm led to the blood droplets travelling a maximum horizontal distance of 5361mm (and average maximum distance of 4981mm). The horizontal distance blood droplets may travel upon impact does not appear to follow a linear trend with differing kinetic energy, but is affected by the applied force and release height in a curvilinear relationship. The results provide a valuable tool to bloodstain pattern analysts and investigators in determining search zones within a scene, as well as providing information about the proximity of an individual to an impact event., (Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.)

Genetic profiling of DNA collected from fingerprints that have been exposed to various enhancement techniques is routine in many forensic laboratories. As a result of direct contact with fingermark residues during treatment, there is concern around the DNA contamination risk of dusting fingermarks with fingerprint brushes. Previous studies have demonstrated the potential for cross-contamination between evidentiary items through various mechanisms, highlighting the risk of using the same fingerprint brush to powder multiple surfaces within and between crime-scenes. Experiments were performed to assess the contamination risk of reused fingerprint brushes through the transfer of dried saliva and skin deposits from and to glass surfaces with new unused squirrel hair and fiberglass brushes. Additional new unused brushes and brushes previously used in casework were also tested for their ability to contaminate samples. In addition, the ability to eradicate DNA from used squirrel hair and fiberglass fingerprint brushes was assessed using a 1% sodium hypochlorite solution and a 5% solution of a commercially available alternative, Virkon. DNA profiling results from surfaces contacted by treated and untreated brushes were compared to determine the effectiveness of the devised cleaning protocol. Brush durability was also assessed over multiple wash/rinse/dry cycles with both agents. Varying amounts of DNA-containing material were collected and transferred by squirrel hair and fiberglass brushes, with detectability on the secondary surface dependent on the biological nature of the material being transferred. The impact of DNA contamination from dirty fingerprint brushes was most apparent in simulations involving the transfer of dried saliva and brushes previously used in casework, while minimal transfer of touch DNA was observed. Alarmingly, large quantities of DNA were found to reside on new unused squirrel hair brushes, while no DNA was detected on new unused fiberglass brushes or brushes sold as DNA-free. Squirrel hair brushes were easily and effectively cleaned with both hypochlorite and Virkon, with no evidence of DNA transfer between exhibits by treated brushes. Brushes were still deemed useable after multiple cleaning cycles with either agent. In contrast, fiberglass bristles became tangled and matted when wet and could not be cleaned effectively using either method. It is recommended they are disposed of following use. Each laboratory should consider their current circumstances before adapting a cleaning method. The implementation of a program to monitor the effectiveness of the cleaning regime is also advised., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Peer review features prominently in the forensic sciences. Drawing on recent research and studies, this article examines different types of peer review, specifically: editorial peer review; peer review by the scientific community; technical and administrative review; and verification (and replication). The article reviews the different meanings of these quite disparate activities and their utility in relation to enhancing performance and reducing error. It explains how forensic practitioners should approach and use peer review, as well as how it should be described in expert reports and oral testimony. While peer review has considerable potential, and is a key component of modern quality management systems, its actual value in most forensic science settings has yet to be determined. In consequence, forensic practitioners should reflect on why they use specific review procedures and endeavour to make their actual practices and their potential value transparent to consumers; whether investigators, lawyers, jurors or judges. Claims that review increases the validity of a scientific technique or accuracy of opinions within a particular case should be avoided until empirical evidence is available to support such assertions., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Expertise studies in forensic handwriting examination involve comparisons of Forensic Handwriting Examiners' (FHEs) opinions with lay-persons on blind tests. All published studies of this type have reported real and demonstrable skill differences between the specialist and lay groups. However, critics have proposed that any difference shown may be indicative of a lack of motivation on the part of lay participants, rather than a real difference in skill. It has been suggested that qualified FHEs would be inherently more motivated to succeed in blinded validation trials, as their professional reputations could be at risk, should they perform poorly on the task provided. Furthermore, critics suggest that lay-persons would be unlikely to be highly motivated to succeed, as they would have no fear of negative consequences should they perform badly. In an effort to investigate this concern, a blind signature trial was designed and administered to forty lay-persons. Participants were required to compare known (exemplar) signatures of an individual to questioned signatures and asked to express an opinion regarding whether the writer of the known signatures wrote each of the questioned signatures. The questioned signatures comprised a mixture of genuine, disguised and simulated signatures. The forty participants were divided into two separate groupings. Group 'A' were requested to complete the trial as directed and were advised that for each correct answer they would be financially rewarded, for each incorrect answer they would be financially penalized, and for each inconclusive opinion they would receive neither penalty nor reward. Group 'B' was requested to complete the trial as directed, with no mention of financial recompense or penalty. The results of this study do not support the proposition that motivation rather than skill difference is the source of the statistical difference in opinions between individuals' results in blinded signature proficiency trials., (Crown Copyright © 2014. Published by Elsevier Ireland Ltd. All rights reserved.)

The analysis of LCN or highly degraded DNA samples presents a challenge for forensic science. Improving the quantity and/or quality of samples would greatly increase the profiling success rate from LCN and degraded samples. Whole genome amplification (WGA) is one method that has such potential. Two commercially available WGA kits, GenomePlex and GenomiPhi, were investigated for use on LCN and degraded DNA samples. Both kits amplified genomic DNA, producing microgram quantities from sub-nanogram templates. Profiling success of LCN DNA samples was increased, with improvements of over 700% from 10pg template DNA compared to non-WGA-amplified control samples. The amplification success with degraded DNA was also improved by WGA. Degraded DNA was simulated using restriction enzymes to demonstrate that the application of WGA can result in the typing of STR loci that could not previously be amplified. An increase in artefacts, such as stutter alleles and amplification biases, were observed in many samples. Results show that WGA is capable of increasing both the quality and quantity of DNA, and has the potential to improve profiling success from difficult samples in forensic casework.